[PATCH] mutex subsystem, more debugging code

[PATCH] mutex subsystem, more debugging code

more mutex debugging: check for held locks during memory freeing,
task exit, enable sysrq printouts, etc.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@infradead.org>